Airline passengers are more at risk of catching the coronavirus if they sit in a window seat, a new study has found, contradicting the widely held belief that those in aisle seats would be more exposed.
The findings come from a detailed analysis of passengers on a Qantas flight in March during which as many as 11 people were infected.
It also indicated that passengers in the middle of the economy section of the Airbus A330 aircraft were more likely to catch the virus than those in the rear. Sitting within two rows of an infected person was also a risk factor.
The researchers, based at universities and public health institutions in Western Australia, where the Qantas flight landed, said they had not expected to find window seats involved a greater risk of exposure.
"This finding was unanticipated given the widely held view that persons in window seats are at lower risk for exposure to an infectious pathogen during flight," they wrote in Emerging Infectious Diseases.
The prevailing view, they said, had been supported by simulations of respiratory illness transmission during flights of a similar length on planes in the US.
Of the 243 passengers on the five-hour Sydney-to-Perth service, 11 were infectious at the time of travel. Nine of these infectious people had earlier that day disembarked a cruise ship, the Ruby Princess, that suffered a notorious outbreak in which hundreds were infected and more than two dozen died.
The 11 infectious passengers were spread evenly through the economy section of the plane, with six in the mid-cabin section and five in the aft, or rear section.
Detailed genetic study of the coronavirus strains of passengers found that the flight almost certainly resulted in eight people being infected, with a further three possibly infected.
The researchers could more easily work out the pattern of infections on the plane because the passengers from the Ruby Princess had a unique strain of the coronavirus called A2-RP.
Of the 11 coronavirus cases thought to have been caused by the flight, known as secondary cases, seven – or 64 per cent – were among people who had been seated by a window. This finding that window passengers were more likely to be infected was highly statistically significant.
It contrasts with research from 2018, partly funded by Boeing, that found aisle seats were more likely to be contaminated with pathogens because people touched them with their hands or brushed against them as they walked past.
The new study also found that eight of the 11 secondary cases on the flight – on which mask wearing was said to be rare – involved passengers seated within two rows of infectious tourists from the Ruby Princess ship.
Two people possibly infected on the flight were three rows away and one person known to have contracted coronavirus on the flight was six rows from an infectious passenger.
The 2018 Boeing-funded study, which analysed the spread of another coronavirus, Sars, on board aircraft, also suggested passengers seated within two rows of an infectious person were most at risk.
That research considered several ways by which pathogens could spread and found that touching contaminated surfaces was the biggest risk, causing as much of a hazard as close person-to-person contact and contamination from the surrounding air combined.
The aircraft industry has previously argued that the risk of airborne infection on flights is extremely low because of air filtering.
Two years ago, the International Air Transport Association released a report that said filters removed “virtually all viruses and bacteria”.